//棣栧厛鍐欎竴涓被鐨勬�濇兂鏄兂浣犺繖涓猯ist閾捐〃閲岄兘寰楁湁鍝簺鍏冪礌锛屽嵆鍝簺鎴愬憳鍙橀噺璺熸柟娉曟湁绗竴涓粨鐐癸紝鏈�鍚庝竴涓粨鐐�,姣忎釜缁撶偣鐨勫叧绯伙紝鍓嶇粨鐐癸紝涓嬩竴涓粨鐐癸紝缁撶偣閲岀殑鍏冪礌
public class shuangList {
    private Node first;
    private Node last;
    //鍘熼摼琛ㄧ殑鏈�鍚庝竴涓粨鐐癸紝鍘熼摼琛ㄧ殑绗竴涓粨鐐�
    private int size;
    //size琛ㄧず缁撶偣鐨勬暟閲�
    public void addlast(Object ele) {
        Node node = new Node(ele);
        //杩欎釜new鐨勫璞℃槸宸茬煡鐨勯渶瑕佷繚瀛樼殑缁撶偣瀵硅薄锛屽嵆褰撳墠缁撶偣,node閲岃繕甯︾潃鍏冪礌,node杩欎釜瀵硅薄灏辨槸褰撳墠缁撶偣
        if (size == 0) {
            this.first = node;
            this.last = node;
        } else {
            this.last.next = node;
            node.prev = this.last;
            this.last = node;
        }
        size++;
    }
    public String toString(shuangList list) {
    	if(size==0) {
		   return null;
    	 }
    	else {
    		StringBuffer str =new StringBuffer(size*2+1);
    		str.append();
    		return
    		
    	}
    }
    class Node{
        //瀵逛簬缁撶偣node鏈夊墠缁撶偣锛屼笅涓�涓粨鐐癸紝姣忎釜缁撶偣閲屽甫鏈変竴涓厓绱�
        Node prev;
        Node next;
        Object ele;
        public Node(Object ele){
            this.ele=ele;
        }




        }
 }

